In recent years, the scale of flat-screen displays has become greater and greater, allowing use as bulletin boards and signboards providing a large number of observers with various items of information content. Conventionally, there has been proposed a display device provided with a display area for nearby observers and another display area for distant observers. The display area for distant observers is designed to be larger than the other display area for nearby observers. In this display device, both display areas are switched between each other in accordance with a result of detecting relative position and distance of an observer in relation to the display.
However, the conventional display device gives rise to difficulties in switching the display areas when there are a large number of observers. In addition, this display device is not intended to simultaneously display different items of information content to an unspecified large number of observers.